1. Field of the Invention
The present invention relates to a broadcasting receiver that receives broadcastings of predetermined channels transmitted from a plurality of broadcasting stations by using a directivity-switching antenna.
2. Description of the Related Art
In Japan, a broadcasting wave such as a television broadcasting is generally transmitted from one base station. For this reason, a broadcasting receiving antenna is fixed to face the base station at a roof, a veranda of the house and so on, and the antenna and the broadcasting receiver are connected through a cable, so that almost all of broadcastings transmitted from a plurality of broadcasting stations can be received. On the contrary, in other countries such as U.S., each broadcasting wave is individually transmitted from a plurality of broadcasting stations. Therefore, when the antenna is fixed toward one site, a broadcasting of the broadcasting station in a direction that the antenna faces can be received, while a broadcasting of the broadcasting station in the other direction that the antenna does not face cannot be received.
Here, under the above-mentioned circumstances, a broadcasting receiver using an antenna (hereinafter, referred to as a directivity-switching antenna) that can switch directivity, for example, as described in the following Patent Documents 1 and 2 has been developed. The directivity-switching antenna includes a plurality antenna elements and a plurality of phase shifters corresponding to the respective antenna elements, and thus each phase of a signal received through each antenna element is controlled and synthesized by each phase shifter, thus the directivity is electrically changed. For example, a smart antenna as an example of a directivity-switching antenna is specified to change directivity into 16 directions in the specification. A method of controlling directivity-switching antenna is disclosed in Patent Document 3 as well as the following Patent Documents 1 and 2. The broadcasting receiver transmits a control signal to the directivity-switching antenna, and switches the directivity direction of a corresponding antenna into a predetermined direction, so that a broadcasting wave in a predetermined channel transmitted from a predetermined broadcasting station is received. Further, when the broadcasting receiver receives a broadcasting wave of the predetermined channel, it stores information indicating a channel number and a directivity direction of the directivity-switching antenna at that time into a memory (see JP-A-11-298226 and JP-A-2001-168627). At this time, an identification number of a transmission source of the broadcasting wave may be stored (see JP-A-2002-094448).
Even when the directivity-switching antenna is fixed to the roof and so on, as described above, the broadcasting receiver can receive almost all of the broadcastings transmitted from a plurality of scattered broadcasting stations to set a receivable directivity direction of the directivity-switching antenna for each channel. In addition, with this arrangement, when the channels are switched by a remote controller and so on, the broadcasting receiver then reads information indicating the directivity direction in which the broadcasting of the channel after switching can be received from the memory, switches directivity of the directivity-switching antenna into that direction, and directly receives the broadcasting in the same channel. In general, images of broadcasting received by the broadcasting receiver are displayed on, for example, a television receiver (hereinafter, referred to as television), and thus a user can watch the images. In addition, a channel number of the received broadcasting is also displayed on the television so that the user can recognize it.